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Re:An Interesting Pattern in the Prime Numbers: Parallax Com... by airesearcher on Friday May 18, 2018 @08:09PM (#17105869)
The rendering was for n=74 in fact, not for n=75. The pattern does seem to recur for even numbered n values and for those we think it matches GCD (where cells contain an even number of integers, and we render for the same even number of rows). But this has not been proved yet. However when n has odd values, the pattern does not always match GCD, it turns out. This is interesting and means that it may be a less “trivial” pattern in fact.

See the Mathematica notebook, which correctly renders it for any value.

Https://GitHub.com/shaunxcode/a-pattern-in-the-primes

Re:An Interesting Pattern in the Prime Numbers: Parallax Com... by airesearcher on Saturday May 19, 2018 @12:12AM (#17106616)
See this animation by Ian Rust showing how the even values of n approach the GCD pattern as the values increase:

https://streamable.com/l7r96

However, for odd values of n, it does not match GCD. So it's not simply a drawing of the GCD pattern.

Re:An Interesting Pattern in the Prime Numbers: Parallax Com... by svat on Saturday May 19, 2018 @03:45AM (#17107045)
Well, for obvious reasons: when n is odd, and the row R is even (specifically, 2 mod 4, i.e. of the form 4k+2 for some k) and the column C is odd, then even if gcd(R, C) = 1, the set being considered contains only even numbers — note that it starts with R(R-1)N/2+C which will be even as R(R-1)/2 is odd and so is C - so you won't have any primes in it. (That is, you'll have a red cell, even where the gcd pattern has a black one.)

And when n is even, there's also a heuristic argument that there are only finitely many counterexamples; i.e. you should expect to find the pattern from your process exactly match that from just the gcd, beyond a few counterexamples: https://news.ycombinator.com/item?id=17106648

Re:An Interesting Pattern in the Prime Numbers: Parallax Com... by leereeves on Saturday May 19, 2018 @08:15AM (#17107578)
> the even values of n approach the GCD pattern as the values increase

Meaning that the chance of finding a prime in these sequences of N numbers approaches one, after eliminating the cases that make primes impossible (n odd and r=2 mod 4, gcd(r,c) > 1).

Is there any deeper meaning to that, or is it simply that the probability of finding a prime in any sequence of n numbers approaches one as n increases, excluding sequences in which primes are impossible?

Re:An Interesting Pattern in the Prime Numbers: Parallax Com... by macawfish on Saturday May 19, 2018 @12:35AM (#17106682)
This is fascinating!